Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide.
Chlorine is used to purify drinking water. Excess of chlorine is harmful. The excess of chlorine is removed by treating with sulphur dioxide. . Present a balanced equation for this redox change taking place in water.
1 Answers
Answer: We have
The given redox reaction can be represented as:
Cl2(g) + So2(aq) + Cl-(aq) + So42-(aq)
The oxidation half reaction is:
S+4O2(aq) → S+6O42-(aq)
The oxidation number is balanced by adding two electrons as:
So2(aq) → So42-(aq) + 2e-
The charge is balanced by adding 4H+ ions as:
So2(aq) → So42-(aq) + 2e-
The O atoms and H+ ions are balanced by adding 2H2O molecules as:
So2(aq) + 2H2O(I) → sO42-(aq) + 4H+(aq) + 2e- ...............(i)
The reduction half reaction is:
Cl2(g) → Cl-(aq)
The chlorine atoms are balanced as:
Cl02(s) → Cl-1-(aq)
The oxidation number is balanced by adding electrons
Cl2(g) + 2e- → 2Cl-(aq) ............(i)
The balanced chemical equation can be obtained by adding equation (i) and (ii) as:
Cl2(s) + So2(aq) + 2H2O(l) → 2Cl-(aq) + SO42-(aq) + 4H+(aq)